In addition to the well documented neonatal withdrawal syndrome, infants of heroin addicts may experience a 3 to 6 month period of subacute withdrawal symptoms and may continue to show abnormality at one to two years of age, notably subnormal somatic growth, minor neuromotor dysfunction, and behavioral disturbance. Though the relationship of these early disturbances to school problems has not been investigated in addicts' children, Prechtl reported a strong correlation between "hyperexcitable infants" (presumably not drug-related) and later behavioral disorders. Nichtern relates that children of addicts have a variety of learning problems, with an apparent "difficulty in organizing and integrating impulse." Similar neonatal withdrawal signs occur in infants born to mothers maintained on methadone therapy during pregnancy. The immediate and long-term effects of maternal heroin and methadone use upon the infant's developing nervous system must be compared before optimal management of the pregnant addict can be determined. This project proposes to study three groups from birth to school age: infants of heroin addicts, infants of addicts maintained on methadone during pregnancy, and infants of non-drug users of similar sociocultural background. Their growth, development, neurologic status and behavioral characteristics will be related to prenatal factors, neonatal morbidity, severity of neonatal withdrawal symptoms, and character of environment.